import { truncateToWidth, visibleWidth } from "@earendil-works/pi-tui";

import type { GoalSnapshot } from "./types.js";

export interface GoalTiming {
  activeSeconds: number;
  elapsedSeconds: number;
}

export const COMPLETED_GOAL_RETENTION_SECONDS = 30;
export const ACTIVE_GOAL_REFRESH_MS = 10_000;

export function isGoalClockVisible(
  goal: GoalSnapshot,
  now = Math.floor(Date.now() / 1000),
): boolean {
  if (goal.status !== "complete" || goal.completedAt === null) {
    return true;
  }
  return now - goal.completedAt < COMPLETED_GOAL_RETENTION_SECONDS;
}

export function goalClockRefreshDelayMs(goal: GoalSnapshot, nowMs = Date.now()): number | null {
  if (goal.status === "active") {
    return ACTIVE_GOAL_REFRESH_MS;
  }
  if (goal.status !== "complete" || goal.completedAt === null) {
    return null;
  }
  const deadlineMs = (goal.completedAt + COMPLETED_GOAL_RETENTION_SECONDS) * 1_000;
  return deadlineMs > nowMs ? deadlineMs - nowMs : null;
}

export function goalTiming(goal: GoalSnapshot, now = Math.floor(Date.now() / 1000)): GoalTiming {
  const activeDelta =
    goal.status === "active" && goal.activeStartedAt !== null
      ? Math.max(0, now - goal.activeStartedAt)
      : 0;
  const end = goal.completedAt ?? now;

  return {
    activeSeconds: goal.usage.activeSeconds + activeDelta,
    elapsedSeconds: Math.max(0, end - goal.createdAt),
  };
}

export function formatClockDuration(totalSeconds: number): string {
  const seconds = Math.max(0, Math.floor(totalSeconds));
  const hours = Math.floor(seconds / 3_600);
  const minutes = Math.floor((seconds % 3_600) / 60);
  const remainder = seconds % 60;

  if (hours > 0) {
    return `${hours}:${minutes.toString().padStart(2, "0")}:${remainder.toString().padStart(2, "0")}`;
  }
  return `${minutes}:${remainder.toString().padStart(2, "0")}`;
}

export function formatGoalClock(
  goal: GoalSnapshot,
  now = Math.floor(Date.now() / 1000),
): string {
  const timing = goalTiming(goal, now);
  return (
    `Goal [${goal.status}]: ${flattenObjectiveForRail(goal.objective)}` +
    ` | active ${formatClockDuration(timing.activeSeconds)}` +
    ` | elapsed ${formatClockDuration(timing.elapsedSeconds)}`
  );
}

export function renderGoalClockLine(
  goal: GoalSnapshot,
  width: number,
  now = Math.floor(Date.now() / 1000),
  fg?: (color: string, value: string) => string,
): string {
  if (width <= 0) {
    return "";
  }

  const timing = goalTiming(goal, now);
  const heading = `goal ${goal.status}`;
  const active = formatClockDuration(timing.activeSeconds);
  const fixedWidth = visibleWidth(`${heading} ${active} `);
  if (fixedWidth >= width) {
    return truncateToWidth(`${heading} ${active}`, width);
  }
  const objective = truncateToWidth(
    flattenObjectiveForRail(goal.objective),
    width - fixedWidth,
  );
  return styleGoalRailLine(heading, `${active} ${objective}`, fg);
}

/**
 * Goal rail / clock lines must stay one terminal row. Raw objectives can keep
 * newlines for prompts and `/goal` inspection, but embedding them here makes
 * the widget taller than the dock budget and desyncs main-screen differential
 * paints (Working... / Elapsed stacking into scrollback).
 */
export function flattenObjectiveForRail(objective: string): string {
  return objective
    .replace(/[\r\n\t]+/g, " ")
    .replace(/ {2,}/g, " ")
    .trim();
}

function styleGoalRailLine(
  heading: string,
  tail: string,
  fg?: (color: string, value: string) => string,
): string {
  if (!fg) return `${heading} ${tail}`;
  return `${fg("warning", heading)} ${fg("dim", tail)}`;
}